Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
There is an extra coma after the copyright year which tricks
gnulib's update-copyright script.
gdb/stubs/ChangeLog:
* ia64vms-stub.c: Adjust copyright header to follow convention
expected by gnulib's update-copyright script.
